1. Field of the Invention
The present invention relates food products, more particularly to edible flavored liquid oils.
2. Description of the Related Art
Two frequently used flavoring agents are garlic and onion, both of which are members of the lily family. The odor characteristic of each results from derivatives of the amino acid cysteine. The flavor of the onion bulb resides in what is termed onion oil, a sharp-odored yellow liquid, the main component of which is allyl propyl disulfide. Onions contain methyl- and propyl-L-cysteine sulfoxide but little of the allyl form, and a sulfoxide lyase which converts these compounds to dimethyl, dipropyl and methylpropyl thiosulfinates, which are unstable and decompose even further. The characteristic onion-odor is associated with the dipropyl derivative. Stronger onions have higher ratios of propyl to methyl derivatives than milder onions. When the cells are damaged by slicing, crushing, mincing or chewing, the enzyme cysteine sulfoxide lyase converts propenyl-L-cysteine sulfoxide to either thiopropanal sulfoxide, which has been identified as the lachrymator in freshly cut onion tissue. Helen Charley, Food Science 506-508 MacMillan Publ. Co., N.Y.) (2d Ed. 1986) The garlic flavor resides in what is termed garlic oil, which is obtained from steam distillation of garlic. Garlic oilcontains a mixture of terpenes and organic sulfides, including allyl-L-cysteine sulfoxide, or alliin, and the enzyme allinase or cysteine sulfoxide lyasze, which converts ally-L-cysteine sulfoxide to ammonia, pyrovic acid and diallyl thiosulfinate, or allaicin. The last is unstable and decomposes to form diallyl disulfide, the main constituent in garlic odor. The conversion occurs when the cells are damaged by slicing, crushing, mincing or chewing. Id.
Garlic is a controversial flavoring agent; as an herb with a strong and distinctive flavor, it imparts its well-known characteristic flavor to any food with which it is prepared. The flavor is so distinctive that it evokes widely varying individual reactions; it is tolerated by some in small amounts, well-liked by others even in large amounts or intensely disliked. The wide range of tolerance or preference for garlic flavor makes it difficult for a cook to judge how much garlic is appropriate for a particular audience. Fresh garlic is also known to cause an aftertaste. This is thought to result from the volatile garlic flavor being released as a result of chewing and being "burped" up after the meal.
Onion is a less controversial ingredient and is more favorably received than garlic but also has some drawbacks. Onion has extremely volatile flavoring agents which cause eye irritation and stinging. For this reason, many cooks do not like to cut or slice onions. Numerous tricks have been employed to prevent eye tearing while cutting onions--holding the onion under running water, boiling the onion for about 10 seconds and chilling it prior to working with it, using a closed chopping device or special grater designed to contain the volatile agent. Onions also have a lingering odor, which may be gotten rid of with lemon juice, salt, vinegar or rubbing powdered mustard.
Fresh garlic is also perceived as undesirable to work with, as it imparts its distinctive flavor to the porous surfaces of utensils, bowls and the like which come into contact with garlic. Wooden surfaces are especially prone to absorbing garlic flavor, and use of the same utensils to prepare subsequent dishes inadvertently flavors these dishes with garlic. This problem presents the cook with a few options; to continue using the same utensils and tolerating the garlic flavor, to buy a separate set of utensils to use with garlic only, or to prepare garlic-flavored foods with non-porous utensils. Preparation of consistently-flavored small quantities of foods is difficult using traditional flavoring methods. Garlic, for example, is available in cloves, but a single clove is often too much garlic for a single dish, either in terms of the amount prepared or in terms of the amount of flavor desired. The clove may be halved, but this leads to waste and imprecision in measuring.
Variability in the strength of these two flavoring agents also presents difficulties. Some garlic cloves have stronger flavor due to growing conditions and/or individual characteristics of the garlic. The same is true of onions. Recipes also call for one small onion or a clove of garlic; the size of each can vary tremendously. The variation results in the uncertainty as to the resulting flavor of the food.
Another drawback with working with both garlic and onion is that if the food is cooked with these flavoring agents, there is no practical way of adding additional onion or garlic flavor subsequently after the food is cooked or by those who prefer a stronger flavor. This results in a certain amount of guesswork as to the final flavor of the food. Nor is there a satisfactory way for these flavors to be added "to taste" at the table by those who prefer a stronger flavor.
Another drawback of the traditional methods of flavoring with garlic is that as the garlic flavor seeps out of the garlic clove gradually. If heated, the flavoring occurs faster. Therefore, the flavoring process itself is unpredictable and may result in food either overflavored or insufficiently flavored. In addition, over time, the flavor may also change, often getting stronger.
Another concern raised by traditional flavoring methods of garlic flavoring is impact of garlic pieces remaining in the food. In some cases, such as the preparation of a garlic-flavored salad dressing, the presence of a piece of garlic is undesirable, either from an aesthetic point of view or culinary perspective, as a sudden burst of garlic flavor may temporarily overwhelm the food.
One approach to avoid these drawbacks is to use dried onion or garlic as a flavoring agent. This option is not entirely successful as the drying process causes the flavor to deteriorates and provides inferior, often described as rancid, flavor.
Both garlic and onion are available as salts, but these are unsatisfactory both in terms of flavor and if dietary salt is a concern.
A traditional approach to flavoring foods with garlic is to prepare garlic butter, which is made by boiling a few cloves of garlic for about five minutes, crushing the garlic in a mortar and then mixing the butter in with the crushed garlic (Rombauer, I. S. and Becker, M. R., Joy of Cooking, The Bobbs-Merrill Co., Inc., Indianapolis (1975), 351). Garlic butter may also be made by crushing garlic cloves as finely as possible using a mortar and pestle, and blending the garlic with the butter. (La Cuisine. The Complete Book of French Cooking, eds. Letoile, V.-A., Maine, M. and Peter, M., Galley Press, New York (1985), 112). The disadvantage of such an approach is that butter itself is prone to rancidity and thus is not really a suitable medium for long-term use. Unless heated, butter is semi-hard and is not as easily or as accurately measured as liquids. In addition, garlic particles alter the consistency of the butter and result in uneven distribution of garlic flavor within the butter.
Flavored oils are convenient means to flavor foods and are useful as condiments or cooking ingredients. As a liquid, oils are easily measured, mix readily and distribute their flavor more evenly in a dish than a solid flavoring agent.
As a condiment, flavored oil may be used at the table to add flavor to pasta, meat, fish, chicken, pizza or other dishes or, as an ingredient. Pre-flavored oils are useful as marinade and obviate the need to purchase the flavoring agent, which is especially desirable if the flavoring agent is only available in large quantities, such as garlic, in relation to the amount required to prepare a single dish.
Flavored oils have been prepared by prior extraction of the essential flavoring agent such as black pepper to form an herb essence as described in U.S. Pat. No. 3,860,734, which may be subsequently added to oil. This approach is time consuming, requires many steps and special equipment, uses of undesirable chemicals in the extraction process and exposes the volatile flavoring agents to air. Exposure to oxygen and other chemicals may oxidize the flavoring agent or otherwise affect the flavor. Resulting losses or deterioration of the garlic flavor must be compensated for by using larger qualities of garlic, leading to higher cost and waste.
Flavored oils have also been prepared by adding the flavoring agent directly to the oil and leaving the flavoring agent in the oil. For example, pesto, a basil sauce, is prepared by crushing approximately 1 1/2 cups fresh basil leaves, two cloves of garlic, and 1/4 cup pine nuts in a mortar to form a thick puree and adding about 3/4 cup olive oil. (La Cuisine. The Complete Book of French Cooking, eds. Letoile, V.-A., Maine, M. and Peter, M., Galley Press, New York (1985), 112). Leaving the flavoring ingredients in the oil results in a flavored oil of varying strength. The longer the flavoring agents are in the oil, the more flavoring is imparted, and, as a result, the stronger the flavoring over time. Flavor variability makes it difficult for use in recipes which rely on consistent strength and for the home user to assess the strength unless the oil is tested prior to each use.